The present invention relates to a roof opening door device, and more particularly, the present invention relates to a roof door opening and closing device for a roof opening type container used for loading freight, for example, industrial waste, which is to be transported in a closed state.
Generally, when transporting special waste such as industrial waste, or home garbage, in order to prevent the waste or garbage from falling down onto road or the like, the waste and garbage are transported in a state wherein each of them is loaded in a roof opening type container which is capable of being opened and closed at its roof. This roof opening type container is placed on transportation means such as a special vehicle or a train.
Referring to FIG. 3, there is shown a schematic perspective view illustrating a conventional roof opening type container. As can be readily seen from FIG. 3, the conventional roof opening type container has a container body 101 which has a box-shaped configuration. A pair of roof doors 102 are provided to an upper end of the container body 101 in a manner such that they can be opened and closed. The pair of roof doors 102 are manually opened and closed by the medium of manipulation of a handle 103 which is arranged at a front end of the container body 101. When the pair of roof doors 102 are opened and closed by the medium of the manipulation of the handle 103, a reduction gear 105 which is disposed so as to reduce an opening and closing velocity of the pair of roof doors 102, is actuated by continuous rotation of the handle 103. The reduction gear 105 transfers power which is generated by the rotation of the handle 103, through a first chain 104 and a second chain 106 to a pair of gear boxes 112, so that a velocity is reduced.
The pair of gear boxes 112 respectively rotate a pair of driving shafts 109 which extend in a forward and rearward direction at both sides of the container body 101. Each roof door 102 is secured at one widthwise end thereof to each driving shaft 109. The pair of roof doors 102 are rotated about the pair of driving shafts 109 by the medium of rotation of the pair of driving shafts 109 in a manner such that they open or close the upper end of the container body 101.
However, the conventional roof opening type container constructed as mentioned above suffers from defects in that, since power for opening and closing the pair of roof doors 102 is transferred from the handle 103 through the reduction gear 105, the first and second chains 104 and 106 and the pair of driving shafts 109 to the pair of roof doors 102, when the pair of roof doors 102 are initially opened or closed, a great deal of effort is required, and thereby the opening and closing velocity of the pair of roof doors 102 cannot but be slowed. For example, in order to open or close the pair of roof doors 102 through 270xc2x0, while being influenced by a diameter of sprockets which are connected with the first and second chains 104 and 106, the handle 103 must be rotated by about fifty-three revolutions.
Also, when the pair of roof doors 102 are opened and closed, as the center of gravity of each roof door 102 continuously moves, a play is developed in each of the first and second chains 104 and 106, whereby durability of the entire container can be impaired. Moreover, because a sudden roof door sagging phenomenon may be induced due to a self-weight of each roof door 2, the likelihood of an accident to occur is increased.
Accordingly, the present invention has been made in an effort to solve the problems occurring in the related art, and an object of the present invention is to provide a roof door opening and closing device for a roof opening type container, which enables a pair of roof doors to be easily and quickly opened and closed, improves safety upon opening and closing of the roof doors, and enhances durability of the roof doors.
In order to achieve the above object, according to one aspect of the present invention, there is provided a roof door opening and closing device for a roof opening type container, comprising: a pair of roof doors provided to an upper end of a container body which has a box-shaped configuration, in a manner such that the pair of roof doors can open and close the upper end of the container body; a pair of first links having one ends which are pivotably connected to a pair of driving shafts respectively arranged at both sides of the container body and the other ends which are pivotably connected to the pair of roof doors; a pair of second links having one ends which are pivotably connected to two pairs of brackets each pair secured to the upper end of the container body between the pair of driving shafts and the other ends which are pivotably connected to the pair of roof doors; a reduction gear for velocity-reducing rotation force of a handle which is installed on the container body; a link mechanism for transferring the rotation force which is velocity-reduced by the reduction gear, to the pair of driving shafts which are respectively coupled with the pair of roof doors; and a plurality of springs installed on the pair of driving shafts and the two pairs of brackets in a manner such that spring force acts on the pair of driving shafts and the pair of second links when the pair of roof doors are completely opened or closed.
According to another aspect of the present invention, the link mechanism comprises a first chain which is located between the handle and the reduction gear so as to transfer the rotation force of the handle to the reduction gear, a second chain which is located between the reduction gear and the pair of driving shafts so as to transfer the rotation force velocity-reduced by the reduction gear, to the pair of driving shafts, and a pair of connection shafts which respectively connect the pair of driving shafts to the second chain.
According to still another aspect of the present invention, each of the pair of connection shafts and each of the pair of driving shafts are connected with each other by virtue of a pair of gears.
According to yet still another aspect of the present invention, the plurality of springs are installed on the pair of driving shafts and the two pairs of brackets in a manner such that the plurality of springs are freed and thereby the spring force does not act on the pair of driving shafts and the pair of second links when the pair of roof doors are opened by 270xc2x0.